Treatment of nickel and its alloys with calcium and the products therefrom



United States Patent No Drawing. Filed Feb. 8, 1965, Ser. No. 431,223 2 Claims. (Cl. 75-170) This is a continuation-in-part of application Serial No. 302,870 filed October 1, 1963, now abandoned.

My present invention relates to improvements in the treatment of nickel and its alloys and the products therefrom, one object of the present invention being the use of metallic calcium to cleanse the main metal, increase its tensile strength, render the magnetic nickel non-magnetic, and leave within the treated metal such a small percentage as to not leave an amount that may become oxidized and thus impair the base metal, as is the case where over .40 percent is employed.

In order to accomplish the above results, several formulations were employed, one of which was to improve a nickel alloy, in which 60 to 90% of nickel, with 5 to of chromium, and 5 to 10% of molybdenum was employed. This metal without metallic calcium treatment was magnetic, all acids attacked it, and the tensile strength was not as high as when treated as hereinafter set forth.

Example 1 Commercially pure nickel, in sheet form, 78.48%, 10% each of chromium and molybdenum were melted and stirred together, a flux, calcium chloride, was then spread over the top of the melt, then a tungsten rod carrying .40% of metallic calcium enclosed in a small sheet of the same nickel in the melt was projected to the geometrical center of the melt, and the temperature of the melt being greatly above 1585 F., the metallic calcium melted, and the tungsten rod was removed. The melt began to seethe or boil, as in ebullition, and this took from 5 to 7 minutes. When the seething stopped, the flux was skimmed oil, the melt then poured into tube molds for bolt testing, and in fiat form. When the melt was cold, a permanent magnet was used to test the magnetic attraction of the metal, and it was discovered that the cold metal was non-magnetic.

The same melting procedure was carried out using .15% of metallic calcium, and using 25% of metallic calcium, and it was found that the melting using .25% of metallic calcium produced the best final product, and one that could be remelted and not lose its qualities. This 25% metallic calcium treated nickel alloy, by a test made by the U.S. Testing Company, showed 0.01% of metallic calcium, such a small trace as to not .be oxidized, as is the case when more than .40% of metallic calcium is employed.

3,259,493 Patented July 5, 1966 This nickel, chromium-molybdenum alloy was subjected to acid rets, and neither sulphuric, nitric, or hydrochloric acids attacked it, it having been discovered that aqua regia was the only acid that attacked it. The alloy has greater tensile strength than the untreated alloy, and under salt water tests it showed no attack. This. metal can be lathe worked, rolled into thin sheets, and as it has strength and withstands high temperatures above 3700 F. It is suitable for jet rotors and casings. It has a high luster.

When commercial nickel alone was treated as above, using 25% of metallic calcium, the completely treated nickel was non-magnetic, non corrodible, and its tensile strength increased.

From the foregoing, the tests showed that the quantities of metallic calcium retained in the melt must be not more than 0.01% of the melt, that .25% is the preferred percentage calcium for addition to the melt, but that .15% of metallic calcium can be added to the melt with fair results. -In all cases, the residual metallic calcium in the melt is so low that there is no danger of the same oxidizing and thus causing spots in the treated metal either with holes where the lime is formed, or cavities within and on the surface of the metal, particularly when the metal is tooled in the lathe, or holes are bored for bolts or screws.

I claim:

1. A process for producing a non-magnetic high nickel alloy comprising the steps of:

(a) forming a melt of up to 10% by weight chromium, up to 10% by weight molybdenum and the balance essentially nickel;

( b) spreading a calcium chloride fluxing material over the upper surface of said melt;

(c) plunging from about .15 to .25 by weight calcium to approximately the geometric center of said melt, holding the calcium in the melt until it has been completely disintegrated to uniformly distribute calcium throughout the melt; and (e) solidifying said melt by allowing it to cool to a temperature below the melting temperature of said melt to form a non-magnetic nickel base alloy. 2. A non-magnetic nickel-base alloy consisting essentially of up to 10% chromium, up to 10% molybdenum, about 0.01% calcium, and the balance essentially nickel.

References Cited by the Examiner UNITED STATES PATENTS 1,824,966 9/1931 Pilling -170 FOREIGN PATENTS 104,198 6/1938 Australia. 3 11,799 5/ 1929 Great Britain.

DAVID L. RECK, Primary Examiner.

R. O. DEAN, Assistant Examiner. 

2. A NON-MAGNETIC NICKEL-BASE ALLOY CONSISTING ESSENTIALLY OF UP TO 10% TO CHROMIUM, UP TO 10% MOLYBDENUM, ABOUT 0.01% CALCIUM, AND THE BALANCE ESSENTIALLY NICKEL. 